Signaling systems



Jan. 13, 1959 FIG.

TONE SIGNAL R. P. BOYER, JR 2,869,046

SIGNALING SYSTEMS Filed April 1'7, 1956 START TONE CCTT TONE IN //v l E/V TOR RICHARD R BUYER ATTORNEY 2,869,046 Patented Jan. 13, 195i) "Free SIGNALING SYSTEMS Richard P. Boyer, Jr., Rochester, eral Dynamics Corporation, poration of Delaware N. Y., assignor to Gen- Rochester, N. Y., a cor .'Ihis invention relates to signaling systems and partrcularly to the formation and transmission of audible signals over telecommunication channels.

The object of the invention is to provide means particularly adaptable to distant unattended stations for producing and immediately dispatching signals of a type for which continuously operating machines are required in large oflices in metropolitan centers.

It is conventional to employ a means to signal from the distant end, the successful seizure of a facility such as a trunk. Such a signal, by way of example, is the familiar beep-beep heard by an originating operator when she has seized a trunk to a distant point and where in response thereto a distant operator has been connected in circuit or where, in response thereto, a distant selective switch has been appropriated and is now ready for operation. The present invention is embodied in a signaling circuit, which when triggered will automatically enable a tone source and thereupon cause a timed sequence of relay operations to produce such a familiar signal. The said timed sequence of relay operations is believed to be unique in'its simplicity, depending merely upon the combination of the windings of the relays and a capacitative element for each which, through a sequence of charging and discharging operations, times the operation of the relays.

A feature of the invention is the combination of a relay having a pair of windings differentially wound with respect to each other, one of which terminates in one pole of a source of direct current and the other of which terminates in the other pole of a source of direct current with a condenser interposed therein. By this means the condenser remains normally charged. When the midpoint of the two windings is then connected to that pole of the battery to which the condenser is connected, the relay tends to respond to the energization of its other winding but is delayed in this response by the discharge of the condenser through the other winding. When this operating connection is later removed, the condenser will again become charged and during the charging period, now through both windings of the relay in series, the release of the relay is delayed. By means of two such relays a signal circuit may be fabricated so that a characteristic signal consisting of two closely spaced successive spurts of tone may be transmitted.

Another feature of the invention is a circuit controlled by a pair of relays which operate in a given sequence, sharing a common timing condenser. In this arrange ment the condenser first discharges through a winding of one relay to render it slow to operate, then charges through-the winding of a second relay to render it slow to operate and, lastly, discharges through the winding of the first relay again to render it slow to release. Thus the condenser serves the first relay to slow both its operate and release time and between times serves the second relay in a similar manner.

Other features will appear hereinafter.

The drawings consist of a single sheet having three figures, as follows:

Fig. 1 is a schematic circuit diagram showing the use of individual timing condensers with each relay of a pair of signaling relays;

Fig. 2 is a schematic circuit diagramshowing the use of a common timing condenser for both relays of a pair of signaling relays; and

Fig. 3 is a timing chart showing the formation of a characteristic signal by a pair of relays.

In Fig. 1 it may be noted that a tone coming from the tone circuit 1 will pass through a front contact of the start relay 2 through a back contact of the B relay 3, a back contact of the A relay 4, a condenser 5, to a use circuit 6. When the A relay 4 operates, then a connection is made from battery through a back contact of the B relay 3, through a front contact of the A relay'4, and thence to the use circuit 6. Later, when the B relay 3 has operated, the tone may again be traced through a front contact of the B relay 3, a front contact of the A relay 4, to the use circuit 6. Upon the release of the A relay 4, ground is connected through a front contact of the B relay 3, a back contact of the A relay 4 to the use circuit. r

The connection of the tone through the contacts of the A and B relays in Fig. 2 is exactly the same as that above described.

In Fig. 1 a key 7 represents any type of circuit closure which may be employed to enable this tone circuit. When the key 7 is closed the relay 2 will be operated'in an obvious circuit. Through a front contact of this relay, the start conductor to the tone circuit 1 is grounded which will enable the tone circuit and cause a tone to be-transmitted therefrom to the front contact of the start relay 2 and thence over the circuit above described.- The operation of the start relay also extends ground over its front contact, thence over a back contact of the B relay 3 to the junction between the two windings of the A relay 4. Current passing through the upper winding of this relay 4 to the negative source of battery will tend to operate the relay A. However, the connection of ground to the mid-point between these two windings causes the condenser 8, normally charged through the two windings of the relay A in series, to now discharge through the lower winding thereof. The discharge current, however, is in such a direction that it opposes the energization of Y the upper winding of this relay and therefore slows or retards the operation of relay A. During this period a spurt of tone is transmitted to the use circuit 6.

At the end of this delayed operation of relay A, the ground connected to the circuit by the start relay will be extended through the armature and front contact of the relay A to a mid-point between the two windings of the relay B. This relay has a condenser 9 associated with it in exactly the same sort of circuit as relay A and therefore its operation will be likewise delayed. I

During this delayed period, the relay A will be main-' tained operated over the back contact of relay B. Upon the operation of relay B, the operating circuit for relay A is opened and this relay will tend to release. However, the removal of ground from the mid-point between its two windings now places the condenser 8 directly in series with these two windings and the charging current now set up will relay the release of relay A.' During the time that relayA and relay B are both operated,

that is, during the release time of relay A, the tone circuit will again be closed to transmit another'spurt "of tone over the circuit to the use circuit 6. After the relay A has been released, relay B will be held operated through its own front contact to the ground provided by the start relay 2 so that relay B will remain operated until the key 7 is released. Upon the release of key 7, the relay B will release slowly as the condenser!) becomes charged and thus will delay the closure-of the normal circuit between the lower armature of the start relay 2 and the use 3 circuit so that no tone will be transmitted, say, by a race in which the armatures of relay B could return before the armatures of the start relay succeed in reaching the normal unoperated state.

Looking at Fig. 3 it will be noted that a time chart is provided on the basis of a number of succeeding time intervals. Assuming that the start relay is operated at the beginning of a given time interval, it will be noted that the relay A is delayed in its operation until the end of the first time interval thereafter. Thereupon the relay A is operated and the relay B is energized but delayed in its operation for another time interval. Thereafter the relay B and the relay A are both simultaneously operated until the relay A releases at the end of the third time interval. It will be noted also that the tone signal is transmitted in two spurts, that is during the first and third time intervals. At an indefinite period thereafter when the start relay is released, the relay B will tend to release but will be delayed for one time interval, as herein above described.

'In the circuit of Fig. 2 a somewhat different arrangement is made. In this case there is but a single condenser which is shared by the A relay 11 and the B relay 12. The sequence of operation of the two relays is the same as before, but in this case the A relay is delayed in its operation by the discharge of the condenser 10. Thereafter the relay B is delayed in its operation by the charging of the condenser 10 and lastly the release of the relay A is delayed by the discharging of the condenser 10.

The circuits may be traced as follows. Through the operation of a key 13 the start relay 1 4 is operated, whereupon the tone circuit 15 is enabled and causes a steady tone to be transmitted to the contacts of the B and A relays. The start relay 14 places a ground on the armature and back contact of the B relay leading to the midpoint between the windings of the A relay so that this relay tends to operate through its upper winding. However, a circuit may be traced from ground, a back contact and armature of the relay 'B, through the condenser 10, an armature and front contact of the relay 14-, an armature and back contact of the A relay 11 to the lower winding thereof. This condenser 10 being normally charged, now discharges through the lower winding of the relay A and slows its operation.

Upon the operation of the relay A, a circuit may be traced from ground, a back contact and armature of the relay B, condenser 10, an armature and front contact of the start relay 14, an armature and front contact of the A relay 11, an armature and back contact of the B relay 12, through the lower winding thereof to the negative pole of battery. The condenser 10, now discharged, begins to charge through this circuit and delays the operation of the relay B. During this delay period the relay A is maintained in operation through the armature and back contact of the relay B.

Upon the operation of relay B a circuit may be traced from the negative pole of battery through a resistor 16, a front contact and armature of the relay B, a front contact and armature of the relay A, a front contact and armature of the relay '14, condenser 10, a front contact and armature of the relay B to the lower winding of relay A. Since the ground has been removed from the junction of the two windings of this relay, the condenser 11) now discharges through the resistor 16 and the two windings of the relay A in series and this discharging current is sufficient to delay the release of the relay A. Therefore, the operations of these two relays under control of the single timing condenser 10 is exactly the same in sequence as in the circuit of Fig. l and :as depicted in the time chart Fig. 3.

Thus, by means of this relay circuit in which the relays are timed in their operation by a condenser, the familiar beep-beep tone is transmitted to a use circuit.

What is claimed is:

1. In a telecommunication system wherein audible Signals are transmitted over telecommunication channels and wherein timing means are provided responsive to the seizure of a telecommunication channel to transmit over said channel a code signal denoting the successful seizure thereof, the tone signaling relay network operative to apply a code signal to the channel comprising, a source of tone signal, a start relay, a relay A, a relay B, means for energizing said start relay, an energizing circuit for said relay A including operated contacts of said start relay in series with normal contacts of said relay B, capacitor means connected in the energizing circuit of relay A to cause said relay A to be slow to operate and slow to release, an energizing circuit for said relay B including operated contacts of both said start relay and said relay A, capacitor means connected in the energizing circuit of relay B to cause said relay B to be slow to operate, a first circuit for applying tone to the signal channel from said source of tone signal including normal contacts of both said relays A and B together with operated contacts of said start relay, and a second circuit for applying tone to the signal channel from said tone source including operated contacts of both of said relays A and B together with said start relay, whereby the tone from the tone source is originally applied to the channel when only said start relay is operated and said relays A and B are not operated and disconnected from the channel when only said start relay and said relay A are operated while said relay B is not yet operated, and whereby said tone is reapplied when all of said relays are operated and said tone is again disconnected when said relay A is restored and said relay B together with said start relay only remain operated.

2. In a telecommunication system wherein audible signals are transmitted over telecommunication channels and wherein timing means are provided responsive to the seizure of a telecommunication channel to transmit over said channel a code signal denoting the successful seizure thereof, the tone signaling relay network operative to apply a code signal to the channel comprising, a source of tone signal, a start relay, a relay A, a relay B, means for energizing said start relay, an energizing circuit for said relay A including operated contacts of said start relay in series with normal contacts of said relay B, an energizing circuit for said relay B including operated contacts of both said start relay and said relay A, capacitor means connected in the energizing circuits of said relays A and B to cause said A and B relays to be slow to operate and said relay A to be slow to release, a first circuit for applying tone to the signal channel from said source of tone signal including normal contacts of both said relays A and B together with operated contacts of said start relay, and a second circuit for applying tone to the signal channel from said tone source including operated contacts of both of said relays A and B together with said start relay, whereby the tone from the tone source is originally applied to the channel when only said start relay is operated and said relays A and B are not operated and disconnected from the channel when only said start relay and said relay A are operated while said relay B is not yet operated, and whereby said tone is reapplied when all of said relays are operated and said tone is again disconnected when said relay A is restored and said relay 13 together with said start relay only remain operated.

References Cited in the file of this patent UNITED STATES PATENTS 1,743,711 Field Jan. 14, 1930 2,080,273 Holmes May 11, 1937 2,139,117 Gohorel Dec. 6, 1938 2,339,581 Paulson Jan. 18, 1944 2,473,683 Hines June 21, 1949 2,685,052 Boyer July 27, 1954 FOREIGN PATENTS 987,936 France Apr. 25, 

